Coal dewatering apparatus



Jan, 30 R. H. BRIDGES ETAL COAL DEWATERING APPARATUS 2 Sheets-Sheet 1 v Filed July 27, 1959 PZM Jan. 30, 1962 Filed July 27, 1959 R. H. BRIDGES ETAL CQAL DEWATERING APPARATUS 2 Sheets-5heet 2 INVENTORS.

United States Patent Office 3318.563 Patented Jan. 30, 1962 3,018,563 COAL DEWATERING APPARATUS Raymond H. Bridges, Steelville, and Frederick H. Alexander, Chicago, Ill.; said Bridges assignor to Southwestern Illinois Coal Corporation, Indianapolis, Ind., a corporation Filed July 27, 1959, Ser. No. 829,786 8 Claims. (Cl. 34-95) This invention relates generally to drying or dewatering apparatus and in particular to an apparatus for continuously dewatering coal subsequent to the customary washmg operation.

In the processing of coal, it is desirable to provide a dewatering operation subsequent to the conventional coal washing operation. Since, for example, washed coal in the size range of inch to /2 millimeter may contain in total moisture as much as 20% by weight, it is obvious that eflicient transport and handling of the coal requires a substantial reduction in this moisture content. Conventional dewatering processes involve the use of heat to drive moisture from the coal, apparatus for carrying out such processes having obvious drawbacks in regard to economy and application.

It is an object of the present invention to provide a coal dewatering apparatus which utilizes adjacent, rotating rolls having a water absorbing covering for removing moisture from the coal.

It is a further object of the present invention to provide a coal dewatering apparatus of the type described in which the dewatering rolls are continuously purged of water collected from the coal and of dust collected on the rolls.

It is a further object of the present invention to provide a coal dewatering apparatus of the type described in which the velocity of the coal entering the area between the dewatering rolls substantially equals the linear velllocity of the rolls, thereby minimizing abrasion of the ro s.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims:

FIG. 1 is a perspective view of an apparatus embodying the present invention.

FIG. 2 is a side view of a portion of the dewatering roll structure.

FIG. 3 is a view similar to FIG. 2, but showing a modified form of the dewatering roll structure.

FIG. 4 is a view similar to FIG. 2., but showing a further modified form of the dewatering roll structure.

FIG. 5 is a side View of a further modified form of the dewatering roll structure having portions of the clamping bar structure removed.

FIG. 6 is a side sectional view of a portion of the structure shown in FIG. 5.

Referring initially to FIG. 1, there is shown a frame having side members 11 and 12. The frame supports dual dewatering rolls indicated generally at 13 and 14. Theaxes of rotation of the rolls are disposed in horizontal, parallel relation with the side members 11 and 12 supporting suitable stationary bearings (not shown) for the roll shaft supporting roll 13'. The shaft supporting roll 14 is provided with horizontally moveable bearings as will subsequently be described.

The rolls 13 and 14 are covered with shells or sleeves 16 and 17, respectively, which are located upon the rolls and held in place by means of simple band clamps 18 and 19. The sleeve 16 has suitably bonded to its outer surface a covering or sheath of water take-up material indicated at 21. The sleeve 17 has a similar sheath of water takeup material bonded thereto and indicated at 22. The material making up the sheaths Z1 and 22. may

take the form of conventional vinyl or polyurethane-polyether sponge-like material, or it may take the form of either natural or chemically produced rubber sponge material. As will be evident from FIG. 2, the sleeves and sheaths have a single seam indicated at 23 so that the split sheath assembly may be spread open and either moved vertically into encircling relation with the roll or may be slipped on the roll from one end, the sheath being spread apart to clear the roll bearings.

The bearings for the roll 14 are carried by conventional pillow blocks indicated generally at 224 and slidable upon a stationary track. A compression spring 27 urges the adjacent bearing leftwardly so as to bias the roll 14 against the roll 13. The spring 27 seats against a retainer 26a which is threaded upon an adjusting member 26. Rotation of the adjusting member may thus be utilized to adjust the biasing force urging roll 14 against the roll 13. It will be understood that the end of the shaft opposite that shown in FIG. 1 also is provided with adjustable bearings identical to that just referred to. The positions of the axes of rotation of the rolls are thus such that at the area of tangency, indicated generally at 2 8, the sponge-like material is compressed with the magnitude of this compression being adjustable.

Power means for driving the rolls in opposite directions and at equal speed includes the drive motor 29 mounted upon frame member 11. The drive motor rotates a shaft 31 journaled in the bearing 32 carried by the frame. Keyed to the shaft 31 is a spline gear 36 which drives the face gears 34 and 36. The gear 34 is keyed to the central shaft of the dewatering roll 21 and the gear 36 is keyed to the central shaft of the dewatering roll 22'. Rotation of the drive motor thus serves to rotate the dewatering rolls in opposed directions, as indicated by arrows in FIG. 1.

The means for delivering coal in a relatively finely divided state to the area of tangency of the dewatering rolls includes a chute having side members 41 and 42 and a depending transition plate 43. A conveyor belt 44 passes over a roller journaled at 46 in the chute side members and transfers coal to the transition plate 43. The plate is provided with outwardly directed ears 47 which serve to transform the shape of the stream of watered coal into a relatively fiat configuration having a width substantially equal to the width of the water takeup sheath on the dewatering rolls.

Brackets 48 and 49 extending upwardly from the side members 11 and 12, respectively, rotatablv support the central shaft 51 of a squeeze roll 52. The extending end of the shaft 51 carries a sheave 53 which is driven by means of a belt 54, in turn driven by a sheave (not shown) rotationally locked with the face gear 36. The squeeze roll 52 is positioned with relation to its adjacent dewatering roll such that considerable compression is exerted upon the sponge-like sheath of the dewatering roll, thereby serving to squeeze or wring from the dewatering roll moisture which has been picked up from the coal entering the apparatus. A drainage plate 56 catches the water removed from the dewatering roll and channels it to a suitable waste outlet (not shown).

The dewatering roll 14 is provided with an identical squeeze roll 57 supported upon a shaft 58 journaled in brackets 59 carried by the frame. The extending end of the shaft 58 carries a sheave 61 which is driven by means of a belt 62 from a sheave (not shown) rotationally locked to the face gear 34. A drainage plate 63, similar in shape and function to the plate 56, is provided adjacent the roll 57. While not shown in the drawings it will be understood that the squeeze roll shafts might be mounted by means of a pivotally supported bracket, or similar means, whereby the position of the squeeze rolls could be adjusted to determine the force with which .on the sponge-like surface of the dewatering rolls.

the squeeze rolls bear against their adjacent dewatering rolls.

Means for purging or removing dust collected on the dewatering rolls includes a power driven blower indicated generally at 66, and having its inlet connected by means of a tube 67 to a hood 68. 'The hood 68 is sized so that it overlies a portion of the dewatering roll 21 and serves to draw dust therefrom when the blower unit is in operation. It will be understood that this relatively simple means for directly exhausting fine particles picked up by the dewatering rolls might be further elaborated on by the provision of impingement plates and brushes rotating against the dewatering rolls within the hood to cause a decrease in air velocity and to permit collecting of the coal particles removed from the dewatering rolls. While only one purging unit is shown in the drawing, it will be understood that a similar unit (not shown) is also provided for the dewatering roll 14.

In operation, coal is transported by the belt 44 and dropped onto the substantially vertical transition plate 43. The plate serves to shape the coal stream so that as it passes, substantially by free-fall, into the area of tangency of the dewatering rolls, the maximum number of coal particles are contacted by the rolls. As the coal particles pass between the rolls, their surface contact with the rolls transfers moisture from the wet coal to the rolls. neath the rolls into cars or onto further conveyor belts. Simultaneously the squeeze rolls 52 and 57 and the purging units maintain the dewatering rolls in a condition such that relatively clean, dry sponge-like surfaces are continuously presented to the incoming coal.

The incoming coal conveyor is disposed above the dewatering rolls so that as the coal falls substantially freely across the transition plate 43, it will acquire a velocity so as to approximately equal the linear velocity of the rotating dewatering rolls. This arrangement provides a minimum of abrasive effect of the coal particles It will be understood that providing for free fall of the coal particles is a convenient means for providing them with the required velocity. A means for accelerating the particles to the desired velocity other than by the utilization of the force of gravity might also be incorporated in the apparatus. In this event the disposition of the conveyor might be accordingly varied.

It should be noted that the mounting arrangement for the rolls 13 and 14 is such that the rolls may separate during their operation without interrupting their drive from the motor 29. This permits the adjustment of the force exerted by springs 27 to determine the desired amount of compression between the rolls as required by the particular size range of coal being processed. This separability of the rolls also provides a safety feature in the event that a relatively large lump of coal should be included in the specific coal size range being processed. It will be understood that drive arrangements other than the face-gear type of drive herein disclosed might be utilized to permit separability of the rolls.

It will be further understood that, while only one pair of counter-rotatingdrying rolls have been shown, the coal to be processed might be passed through a series of dewatering rolls. Such multiple passes through dewatering rolls might be required where a single pass through the rolls failed to remove the required amount of surface moisture.

Alternate forms of roll sheaths are shown in FIGS. 3 .and 4. The construction of FIG. 3 difiFers from that shown in FIG. 2 in that the sheath is formed of two semi-circular sections with the outer sponge-like material bonded to the sections 16a and 16b and to each other along the joints 23a. This two-piece construction provides ease of handling and, as does the construction of FIG. 2, permits the use of bearings at each end of the roll shaft.

In the construction of FIG. 4, a unitary cylindrical The coal is subsequently discharged from beshell 160 has bonded thereto a sponge-like outer sheath bonded thereto a sponge-like outer sheath joined at the cemented joint 23b. The inner face of the shell carries a key 20 which mates with the appropriate slot in the dewatering roll. This construction has the advantage that the bonding of the sponge material may be accomplished in the shop, that is, this bonding operation need not be carried out at the point of installation of the rolls. This arrangement requires cantilevered shafts for the dewatering rolls so that the shells can be slipped into place from one end of the rolls without disassembling the bearings.

Referring now to FIGS. 5 and 6 a further modified form of the dewatering roll structure is described. The roll is formed of a cylindrical steel tube having an end plate 81 welded thereto, the end plate carrying a hub 81a adapted to receive the roll shaft 80b. Only one end of the roll is shown and described, however, it will be understood that the opposite end of the roll is identically formed. As may best be seen in FIG. 5 the tube and end plate have a radial slot formed therein and a plate 82, generally U-shaped in cross-section, is received within the slot.

In this construction the sheath or backing 83 is formed of a flexible material such as canvas, neoprene impregnated nylon or the like. The sponge-like material 84 is cemented or otherwise bonded to the Outer surface of the sheath with the marginal area of the sheath at each end extending beyond the sponge-like material. The free ends of the sheath are detachably joined at 86 by any suitable means. The joined marginal areas of the flexible sheath are forced into the space bounded by the plate 82 by means of a clamp bar 87 thereby tightening the sheath about the roll structure. The upper marginal area of the clamp bar 87 may be provided with a strip of sponge-like material 88 cemented or otherwise bonded to the bar. 'The strip 88 provides an uninterrupted surface of spongelike material around the exterior of the roll.

The means for tightening the clamp bar will be evident from FIG. 6. An extending, reduced end portion 87a of the bar 87 protrudes between the upstanding arms 89 of a yoke 91 and is attached thereto by a pin 92, the pin extending through registering apertures in the yoke arm and the end portion of the yoke. Threaded through the base of the yoke is a stud 93 which extends through a slot 94 in a boss 95 welded on the end plate 81. It will be understood that by means of the stud 93 and yoke '91, the clamp bar 87 may be drawn into and held within the radial slot.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

l. Acoal dewatering apparatus comprising a frame, dual dewatering rolls supported within said frame on horizontal parallel rotational axes, each of said dewatering rolls including a cylindrical outer sheath of spongelike material and positioned so that said sheaths are compressed as said dewatering rolls move through their area of tangency, power means for driving said rolls in opposite directions and at equal speed, means for releasing coal to be dewatered at a height above the area of tangency of said rolls such that the velocity of the coal is substantially equal to the linear velocity of said dewatering rolls as the coal enters the area of tangency between said dewatering rolls, power driven squeeze rolls spaced from the area of tangency of said dewatering rolls and adapted to compress the sponge-like sheaths of said dewatering rolls to remove moisture therefrom, and means for applying a pressure less than atmospheric to said dewatering rolls for purging them of dust accumulated during coal dewatering.

2. A coal dewatering apparatus as claimed in claim 1 in which each dewatering roll sheath comprises a cylindrical sleeve having an outer covering of sponge-like material, said sleeve and covering having a single longitudinal seam therein permitting installation of the sheath on its dewatering roll without demounting the roll.

3. A coal dewatering apparatus as claimed in claim 1 in which each dewatering roll sheath includes a twopiece sleeve formed of cylindrical segments, each of said sleeve pieces having an outer covering of sponge-like material.

4. A coal dewatering apparatus as claimed in claim 1 in which each dewatering roll sheath includes a seamless cylindrical sleeve having an outer covering of spongelike material.

5. A coal dewatering apparatus comprising a frame, dual dewatering rolls supported within said frame on horizontal parallel rotational axes, each of said dewatering rolls including a cylindrical outer sheath of spongelike material and positioned so that said sheaths are compressed as said dewatering rolls move through their area of tangency, power means for driving said rolls in opposite directions and at equal speed, means for releasing coal to be dewatered at a height above the area of tangency of said rolls such that the velocity of the coal is substantially equal to the linear velocity of said dewatering rolls as the coal enters the area of tangency between said dewatering rolls, and power driven squeeze rolls spaced from the area of tangency of said dewatering rolls and adapted to compress the sponge-like sheaths of said dewatering rolls to remove moisture therefrom.

6. A coal dewatering apparatus comprising a frame, dual dewatering rolls supported Within said frame on horizontal parallel rotational axes, one of said axes being displaceable relative to the other, each of said dewatering rolls including a cylindrical outer sheath of spongelike material and positioned so that said sheaths are compressed as said dewatering rolls move through their area of tangency, power means for driving said rolls in opposite directions and at equal speed, means for releasing coal to be dewatered at a height above the area of tangency of said rolls such that the velocity of the coal is substantially equal to the linear velocity of said dewatering rolls as the coal enters the area of tangency between said dewatering rolls, said releasing means including a plate having extending vanes which distribute the coal across said rolls, and means coupled to said frame and in pressing engagement with said rolls for removing moisture from said rolls.

7. A coal dewatering apparatus comprising a frame, dual dewatering rolls supported Within said frame on horizontal parallel rotational axes, each of said dewatering rolls including a cylindrical outer sheath of a sponge-like material and positioned so that said sheaths are compressed as said dewatering rolls move through their area of tangency, power means for driving said rolls in opposite directions and at equal speed, means for releasing coal to be dewatered at a height above the area of tangency of said rolls such that the velocity of the coal is substantially equal to the linear velocity of said dewatering rolls as the coal enters the area of tangency between said dewatering rolls, and means coupled to said frame and associated with said rolls for removing moisture therefrom.

8. A dewatering roll for a coal dewatering apparatus comprising a cylindrical roll having end plates thereon, an axial slot in the surface of said roll registering with radial slots in said end plates, a sheath for said roll formed of sponge-like material, said sheath having a flexible hacking joined at its opposed ends to loosely encircle the roll, the marginal areas of said backing adjacent the joined ends being disposed over said axial slot, and a clamp bar extending in overlying relation to the joined ends of said backing and carrying a strip of sponge-like material, and means for drawing said clamp bar into said radial slots to thereby draw said sheath tightly about said roll providing an exterior surface of sponge-like material of substantially uniform diameter around the roll.

References Cited in the file of this patent UNITED STATES PATENTS 1,406,275 Norman Feb. 14, 1922 1,803,767 OKeefie May 5, 1931 1,927,955 Schuster Sept. 26, 1933 2,206,355 Hubbard July 2, 1940 2,207,278 Albrecht July 9, 1940 2,456,009 McLane Dec. 14, 1948 

